Series-parallel switch



Oct. 24, 1961 G. H. WHITE 111 3,005,882

SERIES-PARALLEL SWITCH Filed Sept. 25, 1958 3 Sheets-Sheet 1 INVENTOR Guy H.White 1J1 ATTORNEY Oct. 24, 1961 G. H. WHITE m 3,

SERIES-PARALLEL SWITCH Filed Sept. 25, 1958 5 Sheets-Sheet 2 O 24, 19 1 G. H. WHITE Ill 3,005,882

SERIES-PARALLEL SWITCH Filed Se t. 25, 1958 3 Sheets-Sheet 3 United States Patent 3,005,882 SERIES-PARALLEL SWITCH Guy H. White HI, Farrell, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Sept. 25, 1958, Ser. No. 763,298 Claims. (Cl. 200-11) This invention relates, generally, to electric switches and, more particularly, to switches for changing connections for electrical apparatus from a series arrangement to a parallel arrangement and vice versa.

An object of the invention is to provide a series-parallel switch of a rotary type.

Another object of the invention is to provide a seriesparallel switch which may be mounted inside a container, such as a transformer tank, and operated from outside the container.

A further object of the invention is to provide for adjusting the contact pressure of a series-parallel switch.

Still another object of the invention is to provide for positive transition of the switch members from one posi tion to another.

A still further object of the invention is to provide uniform contact pressure in either the series or the parallel position'of the switch.

Other objects of the invention will be explained fully hereinafter or will be apparent to those skilled in the art.

In accordance with one embodiment of the invention, terminal contact members for the windings of a transformer are so disposed that certain contact members are engaged by two triangular contact plates to connect the windings in series-circuit relation and additional contact members are engaged by moving the plates to connect the windings in parallel-circuit relation. The terminal contact members are mounted on a terminal block and the contact plates are carried by a yoke which is rotated 90 to change from series connection to parallel connection and vice versa. A cam surface on the terminal block and a roller cam follower on the yoke provide for positive transition from one position to the other.

For a better understonding of the nature and objects of the invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawings, in which: 7

FIGURE 1 is a view, in plan, of an electric switch embodying the principal features of the invention;

FIG. 2 is a view, in side elevation, of the switch shown in FIG. 1;

FIG. 3 is a view, in end elevation, of the switch;

FIG. 4 is a view, in perspective, of the switch, portions being cut away for clearnes's;

FIG. 5 is a diagrammatic view showing windings connected in series-circuit relation by means of the switch;

FIG. 6 is a diagrammatic view showing the windings connected in parallel-circuit relation, and

FIG. 7 is a reduced view partly in elevation and partly in section of a driving mechanism for the switch.

Referring to the drawings, and particularly to FIGS. 1 to 4 inclusive, the structure shown therein comprises a terminal block 10 having a plurality of terminal contact members 11 mounted thereon, a rotatable yoke '12 which carries a pair of contactplates 13, and a shaft 1-4 which extends through the yoke 12 and the terminal block 10 and supports and drives the yoke 12. The terminal block 10 may be'molded from any suitable insulating material. Likewise, the yoke 12 may be-molded from an insulating material. The block 10 is provided with mounting holes 15 for attaching the block to suitable supporting means (not shown). Theshaft 14 extends through a centrally disposed opening17'in a hub .18 on the yoke 12 and is attached to the yoke by means of a pin 19 which extends transversely through the hub 18 and the shaft 14.

3,005,882 Patented Oct. 24, 1961 As shown most clearly in FIG. 2, the cont-act members 11 are mounted in the block 10. Each contact member extends through the block and is retained in the block by means of a nut 21 which is threaded onto the member 11. Thus, the contact members 11 may be so mounted that their contact surfaces all lie in substantially the same horizontal plane as shown in FIG. 2.

Each contact plate .13 may be adjusted vertically with respect to the yoke 12. Each plate 13 is supported by an adjusting screw 22 which is threaded into a mounting plate 23. The plate 23 is attached to the yoke 12 by means of a holding screw 24. The screws 22 and 24 both turn freely in the plate 13. Thus, the plate 13 may be raised or lowered by means of the adjusting screw 22 since the plate 13 is retained on the screw 22 between a shoulder on the screw and a washer 25 which is retained on the screw by riveting the lower end of the screw. The screw 24 extends through an opening in the plate 13 which is larger than the screw. Thus, the screw 24 functions as a guide for the plate 13 and also prevents the plate 13 from rotating about the screw 22. In this manner the plates 13 may be adjusted to obtain contact pressure between the plates and the contact surfaces of the contact member-s11. After the contact plates 13 are properly adjusted recesses 20 in the yoke 12 may be filled with an epoxy resin 30 which hardens sufliciently to prevent turning or loosening of the screws 22 and 24.

- A compression spring 26 is disposed on the shaft 14 between the bottom surface of the terminal block 10 and a cotter pin 27 which extends through the lower end of the shaft 14. Thus, the spring 26 biases the yoke 12 downwardly, as shown .in FIG. 2, to maintain contact pressure between the contact plates 13 and the contact members 11.

The block 10 has a circular cam 31 formed integrally therewith. Two roller followers 32 are mounted on opposite ends of the pin 19 in the yoke 12. The cam 31 has oppositely disposed valleys 33 on its surface and oppositely disposed crests 34. Thus, as the yoke 12 is rotated clockwise, as shown in FIGS. 1 and 2, the yoke is raised against the compression of the spring 26 by the rollers 32 riding over the crests 34 on the cam 31. When the yoke is rotated the rollers 32 are disposed in the other pair of valleys 33 in the cam;

Thus, the cam and the followers function to provide positive transition of the yoke from one position to the other and to retain the yoke in one or the other of its two positions in which the contact plates 13 engage certain ones ofthe contact members 11. It will be noted that the contact plates 13 are disengaged from the contact members 111 while the yoke 12 is being rotated from one position to the other.

As shown in FIGS. 5 and 6, three separate windings 35, 36, and 37 are connected to the terminal contact members 11. The windings may be. transformer windings or they may be resistor elements or other electrical members which are to be connected in either series-circuit relation or parallel-circuit relation. .As shown in FIG. 5, the three windings are connected in series-circuit relation. Thus, power may flow through the windings from a line conductor L1, which may be mechanically attached to the block 10 by means of a bolt inserted in an opening 16 and electrically connected to one contact member 11, through the winding 37, one contact plate 13, the winding 36, the other contact plate 13 and the winding 35 to a line conductor L2 which may be attached in the same manner as the conductor L1.

It will be noted that each contact plate 13, which is generally triangular in shape, engages twocontact members L1 and a dummy contact point 38. As shown most clearly in (FIGS. 1, 3 and 4, the one contact point 38 or the one dummy contact is a projection on a ridge 39 on the block 10. The other dummy contact point 38 is disposed oppositely from the first point 38 and is a projection formed on the block 10. The points 38 are at the same level as the contact surfaces of the contact members (11. Thus, equal pressure is maintained between the contact plates 13 and the contact members 11 when the switch is in the series position.

As shown in FIG. 6, the windings 35, 36, and 37 are connected in parallel-circuit relation. Each contact plate 13 engages three contact members 11. Thus, power may flow from the line conductor L1 and the one contact plate 13 through the three windings 35, 36, and 37 to the other contact plate 13 and the line conductor L2. As shown in FIGS. 1 to 4, the switch is in the parallel position. As previously explained, the switch may be actuated to the series position by rotating the yoke 12 through 90 by means of the shaft 14.

It will be noted that the three contact members 11 at one side of the shaft 14 are disposed to form an equilateral triangle. Likewise, the three contact members at the other side of the shaft form a similar equilateral triangle. The distance between the bases of the two triangles is substantially the same as the length of one side of either triangle. Also, the distance between a point 38 and a contact 11 is equal to the distance between contacts.

As shown in FIG. 7 the switch may be mounted inside a transformer container 41, only a portion of which is shown. It will be understood that the terminal block 10 may be supported in the container in any suitable manner. The shaft 14 may be connected to a driving shaft 42 by means of a universal coupling 43. The shaft 42 may extend through a tapered bearing 44 in the wall of the container 41. The shaft 4 2 may be rotated manually or by any suitable mechanical means. The combination of the universal joint 43 and the tapered bearing 44 provides for proper positioning and operation of the yoke 12 in spite of slight angular misalignment of the switch mechanism.

As previously explained, the spring 26 on the lower end of the shaft 14 maintains proper contact pressure between the contact plates 13 and the contact members 11. This spring also functions as a bearing for the shaft 14. The spring twists in axial rotation without causing any appreciable torque against the rotation of the shaft.

From the foregoing description it is apparent that the invention provides a switch which may be utilized for changing electrical connections from series-circuit relation to parallel-circuit relation and vice versa. The switch may be mounted inside a container for electrical apparatus and readily operated from outside the container. It is simple and rugged in construction and, therefore, will operate with a minimum amount of maintenance.

Since numerous changes may be made in the above described construction, and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all matter contained in the foregoing description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. In a switch for changing electrical conductors from series to parallel circuit relation, in combination, a terminal block, a plurality of contact members mounted on said block and having surfaces disposed in substantially the same plane, a yoke rotatable about an axis perpendicular to said plane, a pair of generally triangular-shaped plates carried by said yoke and rotatable in the plane of said contact surfaces, additional points on said block in substantially the same plane as said contact surfaces,

each of said plates engaging two of said contact members and one of said adidtional points when the yoke is in the series position, and each plate engaging three contact members when the yoke is in the parallel position.

2. In a switch for changing electrical conductors from series to parallel circuit relation, in combination, a terminal block, a plurality of contact members mounted on said block and having surfaces disposed in substantially the same plane, a yoke rotatable about an axis perpendicular to said plane, a pair of generally triangularshaped plates carried by said yoke and rotatable in the plane of said contact surfaces, each of said plates engaging two of said contact members when the yoke is in the series position, each plate engaging three contact members when the yoke is in the parallel position, and oppositely disposed projections on said block engaging said plates when the yoke is in the series position.

3. In a switch for changing electrical conductors from series to parallel circuit relation, in combination, a terminal block, six contact members mounted on said block and having surfaces disposed in substantially the same plane, a yoke rotatable about an axis perpendicular to said plane, a pair of generally triangular-shaped plates carried by said yoke and rotatable in the plane of said contact surfaces, two projections on said block in the same plane as said contact surfaces, each of said plates engaging two of said contact members and one of said projections when the yoke is in the series position, and each plate engaging three contact members when the yoke is in the parallel position.

4. In a switch for changing electrical conductors from series to parallel circuit relation, in combination, a terminal block, six contact members mounted on said block and having surfaces disposed in substantially the same plane, a yoke rotatable about an axis perpendicular to said plane, a pair of generally triangular-shaped plates carried by said yoke and rotatable in the plane of said contact surfaces, two projections on said block in the same plane as said contact surfaces, each of said plates engaging two of said contact members and one of said projections when the yoke is in the series position, each plate engaging three contact members when the yoke is in the parallel position, a shaft for supporting and driving said yoke, said shaft extending through said block and movable axially in said block, and a spring on said shaft for biasing the yoke toward the block.

5. In an electric switch, in combination, a terminal block, six contact members mounted on said block and having surfaces disposed in substantially the same plane, three of said contact members being disposed to form an equilateral triangle, the other three contact members forming a similar equilateral triangle, the distance between bases of said triangles being substantially the same as the length of one side of either triangle, a yoke rotatable about an axis perpendicular to said plane, a pair of generally triangular-shaped plates carried by said yoke and rotatable in the plane of said contact surfaces, each of said plates engaging two of said contact members when the yoke is in one position, and each plate engaging two contact members and a third contact member when the yoke is rotated to another position.

References Cited in the file of this patent UNITED STATES PATENTS 676,098 Popin June 11, 1901 1,343,109 Byerly June 8, 1920 1,626,423 Harrington Apr. 26, 1927 1,786,391 Grover Dec, 23, 1930 1,831,886 Ross Nov. 17, 1931 2,163,069 Stringer June 20, 1939 2,619,621 Brown Nov. 25, 1952 FOREIGN PATENTS 82,989 Netherlands Oct. 15, 1956 138,414 Switzerland May 1, 1930 605,675 Great Britain July 28, 1948 

